Using liquid CaCl question

[raysmithtx]

I have the version of Brun water that allows the use of liquid CaCl. I measured by SG and know the solution is 13%.

My question is about the measurement. The spreadsheet does not change the 'type' of measurement and for example shows to use 12.16 grams of liquid CaCl. Is that correct? I use grams? Or is it something else like ml?

As you can tell I am not a 'sciency' type of person.

 

[mabrungard]

To simplify the user interface, I specifically avoided the switch between mass and volume based units with respect to the liquid calcium chloride measurement. So, just as you measure your solid salts by mass, you can also measure out your liquid salts as a mass also.

While it would be great to be able to use a hydrometer to measure the specific gravity of calcium chloride solutions for use in Bru'n Water. Unfortunately, most brewing hydrometers don't have a great enough range to measure high percentage solutions. Therefore, measuring out a known VOLUME of the solution and then measuring its MASS is the alternate way of determining the specific gravity of a solution. Having an accurate volume measure is an important thing and for that, a good, laboratory graduated cylinder is therefore important too. Just be sure to subtract the tare weight of the cylinder when assessing the mass of the liquid in the cylinder.

 

[raysmithtx]

To simplify the user interface, I specifically avoided the switch between mass and volume based units with respect to the liquid calcium chloride measurement. So, just as you measure your solid salts by mass, you can also measure out your liquid salts as a mass also.

Thanks for the prompt response. I love Brunwater BTW.

 

[ajdelange]

I have the version of Brun water that allows the use of liquid CaCl. I measured by SG and know the solution is 13%

What SG did you measure?

 

[raysmithtx]

What SG did you measure?

1.120 using a calibrated digital refractometer and confirmed it with my hydrometer.

 

[ajdelange]

1.120 using a calibrated digital refractometer and confirmed it with my hydrometer.

Using that in the formula at
https://www.homebrewtalk.com/showthread.php?t=501377

g/L = -684.57 + 175.12*SG + 509.45*SG*SG

you find right away that the solution contains 150.6 grams of CaCl2.0H20 per liter or 150.6 mg/mL. Thus it is a 15.06 % w/v solution (15.06 grams per 100 mL). As a liter of the solution weighs 0.998203*1.120 = 1117.99 grams that is 150.6/1117.99 = 13.47% w/w but clearly you want the w/v strength here. Just divide the amount of CaCl2 you need by that strength/mL to get the number of mL. For example, if you need 5 grams then 5000/150.6 = 33.2 mL.

 

[ajdelange]

Unfortunately, most brewing hydrometers don't have a great enough range to measure high percentage solutions.

Not a problem! Measure out a half liter of the solution in question. It contains half as much CaCl2 as a liter of the solution. Add DI water carefully with stirring (or inverting if you are using a mixing cylinder) to make up to a liter. Now measure the SG of the diluted liquid to determine how much CaCl2 is in the diluted liter of solution. Double that. That is how much is in the original solution per liter.

For example, suppose we have a solution with specific gravity 1.200. It's CaCl2 content is 259.182 g/L. Half a liter of it would contain 129.591 grams per half liter and when made up to a liter, 129.591 g/L. A solution of calcium chloride with strength 129.591 g/L has SG = 1.10385 and that is what we would read (1.104)in this diluted solution. Putting 1.104 into the formula we would get
g/L = -684.57 + 175.12*SG + 509.45*SG*SG = 129.688 which we would then double to 259.376.

Note that the diluted solution weighs 998.203*1.10385 = 1101.82 grams and contains 129.51 grams of CaCl2 meaning the rest, 973.21 grams, is water whereas the half liter weighs (998.203/2)*1.2 = 598.202 grams so that we had to add (1101.82 - 598.202)/0.998203 = 504.5 mL of water to make up the half liter to 1 liter.

Of course we don't have to work with half liters and liters nor do we need the dilution factor to be 1/2. Just dilute the stock solution to whatever volume it takes to get a reading on your hydrometer, read the SG, use the formula to determine g/L for the diluted solution and then multiply by the dilution factor.

 

[JDL]

I used this post to figure out the topic and figured I would post what I saw doing each idea and how close they were.

My CaCl2 solution SG is 1.080.

According to Bru'n Water and my adjustments I should add 34.41 grams of it, so using what mabrungard stated above I tare'd a graduated cylinder and added it, this solution ended up measuring just about 35ml of liquid volume measurement.

When I applied ajdelange's formula I came out with 98.782 mg/mL which equals 9.87 mg per 100 mL. Using this idea I would need 2.84 grams to equal the same effect of the liquid listed on Bru'n Water. So this would end up being 2840/98.782 which equals 28.75 mL.

In the end I used a 10 dollar scale and obviously some of the liquid stayed in the cylinder when I emptied it so I think this is pretty close considering my equipment. I measured the SG with a calibrated with RO water refractometer.

If anyone sees any issues with my process that will improve it next time please let me know and hopefully this helps the next person searching for this information.

 

[ajdelange]

If you know the SG of the solution is 1.080 you also know its density is 0.998203*1.080 (@ 20 °C). If you need 34.41 grams of solution that is 34.41/(0.998203*1.080) = 31.9185 mL. No need to weigh anything. Just measure out 31.9 mL. Do a "quantitative transfer" to your liquor tank. That's a fancy way of saying pour out the 31.9 mL of liquid, refil the cylinder part way full with DI (or RO) water, slosh around, add to tank, repeat.

Assuming Bru'n did the math right you are shooting for 1000*0.0319185/(-684.57 + 175.12*SG + 509.45*SG*SG ) = 0.312 grams CaCl2.0H2O which is 31.9 mL.

Easiest thing to do is just divide the grams of CaCl2.0H2O you need by (-684.57 + 175.12*SG + 509.45*SG*SG ), measure that out and do a quantitative transfer.

 

[Murphys_Law]

Ok, to make sure I understand this correctly...

I change my CACI2 form to "liquid" and using the cells on the excel sheet I get the strength and enter that in cell M21. I then get a weight in grams so I simply weigh my solution (i.e. if it says I need 3 grams of CACI2 the I add 3 grams of the liquid solution).

Is this correct?